each textile processing stage is given. Optimum colours of light are also discussed and factors to be taken into account during installation of lighting systems are considered. 3.2.000(58987)
Barnes, J.A. The effect of cockpit lighting systems on multicoloured displays Dec 1970; abstr, in US Government Research and Development Reports (Report No AD-716 610/ The report analyses the performance of 42 subjects reading aircraft instruments comprising various combinations of pointer/background colours viewed with both Army/Navy IPL Red and Air Force Blue-White cockpit lighting systems. The results rank the pointer/background colour combinations according to the least number of scale-reading errors they produced.
Noise 3.2.00O(590OO)
Sociale, 1970, 18.5, 319.-334;abstr. in Occupational Safety and Health Abstracts The authors investigated the working conditions in an aircraft factory where workers were particularly exposed to noise; 91 of them underwent complete medical, audiometric and biological examinations. 27% of them were found to have normal hearing, while 62% were suffering from occupationally-induced hearing loss, and 7% from minor complaints attributable to previous ear disorders; 3% of the persons examined had irreversible hearing loss. Certain psychological factors must be taken into account when diagnosing these complaints. The authors discuss the noise-suppression measures taken (exhaust silencers, soundproof cabins, noise barriers to protect workers in other parts of the factory, earmuffs and helmets, rest periods equal to the .square of the exposure time). These measures have proved effective; no changes in audiograms were observed during the period 1965 - 1968.
Grebig, K. 'The fight against noise in industry (in German) Heizung L~[turtg Klimatechnik Haustechnik, 1971, 22.4, 143-146. in the past, industrial noise was accepted as an inevitable accompaniment of industrial progress. Today some effort is being made to reduce noise to acceptable limits. However, the question how loud noise may be made to count as 'acceptable', that is to day, to cause no physical or mental damage, cannot be answered. On the one hand, a negative mental attitude of someone subjected to noise can increase his actual sensitivity, to the extent of physical damage. On the other hand, a positive attitude to noise, and so-called 'becoming accustomed' cannot prevent both temporary and permanent damage, beyond a limit which varies but little, it has been found that sounds from 30 to 65 phon, Stage i, corresponding to about 30 to 65 dB (A) lead to mental effects, that sounds from 65 to 90 phon, Stage II, corresponding to about 65 to 90 dB (B) to mental and material effects, and that noise from 90 to 120 phon, Stage Ill, corresponding to 90 to ! 20 dB (B) to mental, material and otolog=cal effects or damage.
3.2.000(59009) Fktchcr, LL. and Loeb, M. Changes in the hearing of personnel exposed to high intensity continuous noise A bstr. in US Government Research and Development Reports (Report No AD-413 81 7) (?haracterlst~cs of the temporary and permanent threshold shifts of personnel acutely exposed to a high intensity noise. The relation of noise exposure to observed hearing loss is presented. Correlations were obtained between noise exposure, as evaluated by the authors, and hearing loss, as determined by post-exposure audiometry. Correlation was sought between reference threshold and initial shift as well as correlation between reference threshold and permanent Ios.s.
and operators. Sensitization was interrupted as an experimental artifact, possibly related to prestimulator~ loudness adaptation involved in continuou.~tone Bekesy audiometry during the post-exposure period. 3.2.000(59011 ) Hill, V.n. Why 92 dBA? American lndustrml tl.~glene Association Journal, 1970, 31.2, 189 19 7; ahstr, in Occupational Safety and Health .4 bstracts The author discusses in detail the theoretical relationship between octave band and dBA noise measurements. and shows how they can be compared. 'A' scale levels are usually lower than the true levels. After measuring 200 actual, typical sources of industrial noise in the chemical industry (power plant, processing machinery, etc) by both methods, the author concludes that dBA levels provide a good indication of the potential health hazard of most industrial noise, and that 92 dBA (as recommended in 1968 by the American Industrial Hygiene Amociation) appears to be a reasonable criterion for regulatory purposes when considering broad-band continuous noise, in borderline cases, however, the results of audiometric tests should overrule the general criteria of excessive noise. 3.2.000(59015 ) Tomlinson, R.W. A tractor noise limit accordmg to predicted driver hcanng loss Proceedings of the Subiect Day on Tractor and Cab Noise, held on 2nd July 1970, at the .National Institute o] Agricultural l:'ngineerin 8, Silsoe, Bedfordshzre, Jan 1971, 9 I1
l'he assumptions required to predict hearing loss for the general case of n o i ~ exposure, varying noise level, varying exposure time, are mentioned. The varymg noise and exposure levels must be reduced to a prediction of a 'typical' level for the normal working week. The procedure 3.2.000( 590101 for obtaining these statistics is Gmstman, H.L. and Reddy, R.P. described. Median audiograms can Auditory sensitization to noise from then be predicted for various exposure dental drills times. Irom statistical data recently Journal of A udttor)" Research, 19 70. published. "I'he.~ predicted a u d i o ~ a m s 10.1, 17- 22 ~lgreed quite closely with median audiograms obtained m a previous Operators o1 dental drills and their patients received pre- and post-operative survey ol tractor drivers. It was al.,a, predicted that ~)5% of the exposed Bekesy a u d i o m e t r y a t 0 - 5 4 kc/s population would be .safeguarded either with pulsed of continuous tones. against deafness disability if the noise rest-retest at 0.5 kcisalways indicated 3.2.000( 59008 ) levels m field work were not greate: reliable audiometry. Pulsed-tone Chemin, Ph., Bramerie, Y. and than 85 dBA. In the existing noise testing elicited generally nonChemin, A. tests, maximum noise is measured and significant threshold shifts, but Noise-its physaopathological for reasons stated it is considered that consequences- the problem of workers continuous-tone elicited an audioa t~O dBA level on a maximum noise metric improvement or sensitization exposed to noise - results of a survey test might correspond to the 85 dBA following dental drill exposure. Dental m aircraft factories (In French) for field levels. drill exposures are safer for patients Revue d'Hygiene et de Meclecine 124
Applied Ergonomim
June 1972